My research is concerned with the detailed chemical structure of proteins, and it can be divided into the following three interrelated objectives: 1. Elucidation of Pathways of Protein Evolution. This mainly involves determination of amino acid sequences of proteins and comparison of these sequences for evidence of homology and evolutionary relationships. This is an exploration of the hypothesis that gene duplication followed by mutations and divergence of structure and function of homologous proteins is the major evolutionary process responsible for the enormous variety of proteins existing today. Many proteins having rather different functions have probably evolved from a common primative structure, and it is possible that sufficient rudiments of the primative amino acid sequence are preserved in modern protein structures to establish a homologous relationship. In addition, the comparison of amino acid sequences of homologous proteins from various organisms can be used to give a solid quantitative basis to phylogenetics. 2. Correlation of Protein Structure and Function. My approach to this objective mainly involves chemical modification of proteins with bifunctional reagents or by affinity labeling, in order to map the three-dimensional structure of proteins, particularly in the vicinity of the active centers. Of course, amino acid sequence analysis and disulfide bridge analysis provide a sound basis for structure function analysis by chemical modification. e. Development and Perfection of New Methods. This involves methods needed for pursuing objectives (1) and (2). In particular, I am interested in developing methods for sequence analysis of peptides separated on a two-dimensional map or fingerprint by high voltage paper electrophoresis.